One of the most important applications of such manipulator arms is in providing remote power manipulators for laboratories using highly radioactive materials. The radioactive environment imposes many constraints on the design of manipulator arms affecting both their design and their performance. In particular, users seek as many degrees of freedom, as many relative configurations, and as great a capacity as possible for load bearing and/or reach. Nonetheless, it is necessary that such performance does not lead to excessive increase of the radial extent and the weight of the assembly, since these parameters are also important.
Preferred embodiments of the present invention improve the design of prior manipulator arms by improving their load performance and reducing their radial extent, while retaining the other advantages of the prior art. These designs seek to combine as far as possible the advantages of arms comprising a linkage of two standard arm components with those of arms comprising a linkage of three standard arm components.